Insulating assemblies and containers

ABSTRACT

Insulating assemblies having improved thermal seals are provided. The insulating assemblies have an interface between a base portion and a lid that has an angled transitional portion and at least one elevation change. The angled transitional portion advantageously improves lid removability, assembly reusability, and resistance to thermal energy transfer.

FIELD OF THE DISCLOSURE

This disclosure relates generally to foam insulation assemblies and tomethods of producing foam insulated articles and, in particular, relatesto insulating structures, such as containers, with a removable lidhaving an improved thermal seal and methods for producing suchstructures.

BACKGROUND

Insulated shippers are commonly used for shipping meal kits,confectionary products, cakes, other perishable goods, and medical itemssuch as vaccines. These insulated shippers are chosen for their abilityto prevent thermal energy transfer between the interior of the shipperand the environment.

Insulated shippers commonly include a box portion or base having acavity for goods and a lid configured to seal the cavity from theenvironment. The base and lid are typically formed from the samematerial. The interface between the base and the lid is responsible forthe greatest thermal energy transfer. As such, the quality of theinterface between the base and the lid can be determinative of theoverall quality of a particular insulated shipper. In other words, poorsealing of the lid onto the base may result in failure of the insulatedshipper and spoliation of the goods inside.

Prior attempts to reduce thermal loss at the interface between the baseand the lid of insulated shippers incorporated shaped edges on both thebase and lid that interlock together, increasing the contact area andtheoretically reducing thermal transfer. For example, zero-clearancelid-base designs, such as the one in FIG. 1 , increase the contact areaby an amount dictated by the overhang of the lid over the lip of thebase. Variations such as the double-groove interlock improve on thezero-clearance design, such as the one in FIG. 2 . Dovetail lid-basedesigns, such as the one in FIGS. 3A-3B, increase the contact area byincorporating a groove in the lid into which a ridge on the base mayfit. However, these prior designs have exceptionally poor reusabilitydue to compression creep, where the insulating structure experiencessmall changes in size and shape over time, and lid breakage when the lidis removed by a user, as depicted in FIG. 3B.

Accordingly, improved insulated shippers are needed for overcoming oneor more of the technical challenges described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanyingdrawings. The use of the same reference numerals may indicate similar toidentical items. Various embodiments may utilize elements and/orcomponents other than those illustrated in the drawings, and someelements and/or components may not be present in various embodiments.Elements and/or components in the figures are not necessarily drawn toscale. Throughout this disclosure, depending on the context, singularand plural terminology may be used interchangeably.

FIG. 1 is a cross-sectional view of an existing lid-base interface knownin the art.

FIG. 2 is a cross-sectional view of an existing lid-base interface knownin the art.

FIG. 3A is a cross-sectional view of an existing lid-base interfaceknown in the art.

FIG. 3B is a cross-sectional view of the lid-base interface in FIG. 3Aafter breakage.

FIG. 4 is a cross-sectional view of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 5 is a cross-sectional view of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 6 is a perspective view in cross-section of an exemplary insulatingassembly in accordance with the present disclosure.

FIG. 7A is a cross-sectional view of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 7B is a cross-sectional view of the lid-base interface in FIG. 7Aduring removal in accordance with the present disclosure.

FIG. 8 is a cross-sectional view of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 9 is a cross-sectional view of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 10 is a cross-sectional view of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 11 is an illustration of exemplary lid-base transition angleprofiles in accordance with the present disclosure.

FIG. 12 is an illustration of an exemplary lid-base interface inaccordance with the present disclosure.

FIG. 13 is a cross-sectional view of an exemplary extension ring inaccordance with the present disclosure.

FIG. 14 is a perspective view in cross-section of an exemplaryinsulating assembly with an extension ring in accordance with thepresent disclosure.

FIG. 15 is a graph of test results for the ISTA 7D 48-hour winterprofile for a number of insulating assemblies.

DETAILED DESCRIPTION

Insulating assemblies and methods for producing insulating assembliesare provided herein including assemblies with improved interfacesbetween the base portion and the lid of the insulating assembly. Inparticular, it has been discovered that shaping the interface betweenthe base portion and the lid with a protrusion having an angledtransitional section can result in improved thermal properties, improvedstructural integrity, improved lid removability, and improved structurereusability. Furthermore, in a preferred embodiment, shaping theinterface between the base portion and the lid to approximate anon-right trapezoid (i.e., a scalene or isosceles trapezoid), or asegment thereof, has been demonstrated to improve the effectiveness ofthe assembly.

Throughout this disclosure, various aspects are presented in a rangeformat. It should be understood that the description in range format ismerely for convenience and brevity and should not be construed as aninflexible limitation on the scope of the disclosure. Accordingly, thedescription of a range should be considered to have specificallydisclosed all the possible sub-ranges as well as individual numericalvalues within that range. For example, description of a range such asfrom 1 to 6 should be considered to have specifically disclosedsub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4,from 2 to 6, from 3 to 6, etc., as well as individual numbers withinthat range, for example, 1, 2, 3, 4, 5, and 6. This applies regardlessof the breadth of the range.

As used herein, the term “about” with reference to dimensions refers tothe dimension plus or minus 10%.

Insulating Assemblies

Insulating assemblies are disclosed herein. In some embodiments, theassembly includes a base portion having a first interface extendingalong a rim thereof, and a lid having a second interface extending alonga rim thereof. The first interface and the second interface may beconfigured to interlock together to form a closed insulated container,i.e., to define an interior volume bounded by the base portion and lid.

As used herein, an “interface” refers to the area on the base portion orthe lid that forms the point of contact between the base portion and thelid. The interfaces are typically shaped or molded so that the baseportion and lid interlock together to form a closed insulated container,thereby reducing thermal energy transfer across the interfaces.

As used herein, “interlock,” “interlock together,” and similar phrasesrefer to the contacting of two components having interfaces that areshaped and/or designed to be joined together and form a closed insulatedcontainer. In other words, the interfaces have complementary shapes,sometimes referred to in mechanical industries as a “male”component/interface joining with a “female” component/interface. Thus,the mere contacting of a component with another component does notresult in an interlock unless the point of contact includes the joiningof two complementary surfaces or structures.

In some embodiments, each of the first and second interfaces have atleast one elevation change, such that the interlock is formed by matingcorresponding elevations changes of the first and second interfaces.

As used herein, an “elevation change” refers to a segment of aprotrusion or channel molded or shaped to form at least a portion of thefirst and second interfaces. For example, an “L”-shaped lip on theinterfaces, when viewed in cross-section, includes an initial flatsurface and an “elevation change” to a second flat surface higher orlower than the initial flat surface. Alternatively, a trapezoidal-shapedprotrusion or channel includes an initial flat surface, a firstelevation change, a second flat surface that is higher or lower than theinitial flat surface, a second elevation change, and a final flatsurface that is normally level with the initial flat surface.

As used herein, the “transitional section” refers to the surfacerepresenting the elevation change. For example, an “L”-shaped lip on theinterfaces includes an initial flat surface, a transitional section, anda second flat surface higher or lower than the initial flat surface. Atriangular-shaped lip on the interfaces includes a first transitionalsection increasing or decreasing the elevation, followed by a secondtransitional section decreasing or increasing the elevation.

In some embodiments, each of the elevation changes comprises a slopedtransitional section relative to the vertical. As used herein, an angleor slope “relative to the vertical” refers to an angle or slope measuredwith 0° representing a perpendicular plane relative to the horizon, and90° representing a plane parallel to the horizon, measured when theassembly is positioned such that the lid is parallel relative to thehorizon. Furthermore, as used herein, an angle measured “relative to thevertical” has a positive angle regardless of whether such angle ismeasured clockwise or counter-clockwise.

In some embodiments, the sloped transitional section of each elevationchange has a slope of between about 2° to about 43°, relative to thevertical. For example, the sloped transitional section of each elevationchange may be between about 5° and 20°, relative to the vertical. Insome embodiments, the sloped transitional section of each elevationchange has a slope of 5° relative to the vertical.

In some embodiments, the base portion is in the form of a containerhaving an open end for receiving the lid.

In some embodiments, the base portion and lid are formed from fusedexpandable foam beads, and the transitional section includes atransition slope of 20/1 foam beads or less. In other words, the slopeof the transition from an initial flat section to the transitionalsection constitutes a “rise,” or elevation change, of less than 20 foambeads over a “run,” or horizontal change, of greater than 1 foam beads.For example, a slope of 10 involves an elevation change of 10 beads overa horizontal change of one foam bead, and a slope of 5 involves anelevation change of 10 beads over a horizontal change of 2 foam beads.When a fused, expanded foam bead has a diameter of approximately 2 mm,the transition section has a slope of less than 20 foam beads per anelevation change of 20 mm. However, bead size varies depending on thematerial used (expandable polystyrene, polylactic acid, or anothermaterial), the molding process, and the density of the molded foam.Furthermore, the quality and structural integrity of an insulatingstructure formed from fused, expanded foam beads depends on the fusingof the beads themselves. Accordingly, the acceptable transition slope isnot determined by a particular length in millimeters, but is insteaddetermined by a length as measured in fused, expanded foam beads.

In some embodiments, the base portion and the lid of the assembly areformed from fused expandable foam beads made from polylactic acid (PLA),polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS),polyethylene terephthalate (PET), polybutylene terephthalate (PBT),rubberized expandable polystyrene (EPS), or other modified EPS. It hasbeen discovered that materials suitable for foaming and molding intoinsulating assemblies that have a resiliency of at least 80% after 24hours of compression particularly benefit from the interface geometriesdescribed herein. Insulating assemblies formed from foam materialshaving a resiliency of 90% or greater have benefitted from theinterfaces described herein, and insulating structures formed from foammaterials having a resiliency of 95% or greater have demonstrated evengreater improvements. For example, PLA-based foam typically have aresiliency of between 90% and 97% and insulating assemblies formed fromPLA-based foam have been shown to benefit significantly from theincorporation of interfaces as described herein.

In some embodiments, the base portion and the lid are formed from amaterial having an R-value of at least 3.8 at 23° C. As used herein, the“R-value” is an insulating material's resistance to conductive heat flowand is calculated using Equation 1:

$\begin{matrix}{R = \frac{❘{\Delta T}❘}{\phi_{q}}} & {{Equation}1}\end{matrix}$

where R is the R-value in ° F.·ft²/BTU·in, ΔT is the temperaturedifference across a barrier in ° F. (such as the wall of closedinsulated container), and ϕ_(q) is the heat flux through the barrier inBTU/(h·ft²). Commercial equipment may be used to measure the R-value ofa particular barrier, such as a Fox Heat Flow Meter from TA Instruments,New Castle, Del., USA. The R-value of a particular foam insulatingassembly is affected by the material used to form the foam beads, thedensity of the foam insulating assembly, the thickness of the walls ofthe insulating assembly, and, of particular note to the presentdisclosure, the quality of the seal between the lid and the basesection. In some embodiments, the R-value at 23° C. is between about 3°F.·ft²/BTU·in° F.·ft²/BTU·in to about 5° F.·ft²/BTU·in. For example, theR-value may be 3° F.·ft²/BTU·in, 3.5° F.·ft²/BTU·in, 4° F.·ft²/BTU·in,4.5° F.·ft²/BTU·in, 5° F.·ft²/BTU·in, or any R-value therebetween. Insome embodiments, the R-value at 50° C. is between about 2.5°F.·ft²/BTU·in° F.·ft²/BTU·in and 4.5° F.·ft²/BTU·in. For example, theR-value may be 2.5° F.·ft²/BTU·in, 3° F.·ft²/BTU·in, 3.5° F.·ft²/BTU·in,4° F.·ft²/BTU·in, 4.5° F.·ft²/BTU·in, or any R-value therebetween. Insome embodiments, the R-value at −10° C. is between 3.5° F.·ft²/BTU·in°F.·ft²/BTU·in and 5.5° F.·ft²/BTU·in. For example, the R-value may be3.5° F.·ft²/BTU·in, 4° F.·ft²/BTU·in, 4.5° F.·ft²/BTU·in, 5°F.·ft²/BTU·in, 5.5° F.·ft²/BTU·in, or any R-value therebetween.

In some embodiments, the closed insulated container passes theInternational Safe Transit Association (ISTA) 7D 48-hour summer profiletest and the ISTA 7D 48-hour winter profile test at an overall weight atleast 20% lower than a conventional EPS assembly. The ISTA 7D testprocedure evaluates the effect of external temperature on a particularinsulated container. Theoretically, an insulated container can be filledwith more, or with colder, thermal sinks so as to lower the overalltemperature of the insulated container. In this way, an otherwise-poorinsulated container can pass the ISTA 7D 48-hour profile tests, but agreater number of thermal sinks or ice packs are required to do so.Therefore, one measure of an improved insulated container that passesthe ISTA 7D 48-hour profile tests is the weight of the container, i.e.,a container that can pass the ISTA 7D 48-hour profile tests that has areduced weight compared to conventional containers must have improvedthermal energy capabilities. The ISTA certifies thermal chambers forperforming and evaluating the results of the 7D test procedures.

In some embodiments, when the lid is interlocked with the base portion,the lid withstands at least 8 pounds of force without being removedafter at least 10 lid remove-and-replace cycles. In other words, theinsulated container is loaded with at least 8 pounds of contents,inverted so that the downward force is applied directly to the lid ofthe insulated container, and allowed to rest for 10 seconds (i.e., a“remove-and-replace cycle”). The size and shape of the lid and baseportion influence the ability for the insulated container to maintainits strength over a greater number of remove-and-replace cycles. In someembodiments, when the lid is interlocked with the base portion, aremoval force necessary for removing the lid changes by less than 10%over 24 hours. In some tests, the insulated container is inverted andallowed to rest for 24 hours. Upon returning to normal orientation, thelid is removed and replaced, and the inversion process is repeated. Uponlid failure while inverted, one pound of contents is removed and theprocess continued. This test measures the effect of “compression creep,”which is a phenomenon common to foam insulated containers that occursover time as an insulating container's lid is removed and replacedseveral times. The fused, expanded foam beads that form the insulatedcontainer experience small changes in size and shape over time,particularly when compressed by, for example, interlocking the lid withthe base portion. As a result, the lid of a typical insulated containerloses integrity over time and fails to remain securely coupled to thebase portion. It has been unexpectedly discovered that shaping theinterface between the lid and base portion as described herein reducesor eliminates the effect of compression creep.

In some embodiments, the first interface of the base portion has twoelevation changes so that the first interface of the base portion formsa protrusion, and the second interface of the lid has two elevationchanges complementing the first interface so that the second interfaceforms a channel into which the protrusion of the first interface isinserted. In other embodiments, the first interface forms a channelwhile the second interface forms a protrusion. In some embodiments, theprotrusion and channel resemble a non-right trapezoid. In otherembodiments, the protrusion and channel resemble a semi-circle,half-oval, triangle, or another shape that has a sloped transitionalportion and at least two elevation changes. For example, an interfaceresembling a semi-circle can be considered as having a first slopedtransitional portion consisting of a quarter-circle that increases ordecreases the elevation by a first amount, and a second slopedtransitional portion consisting of a quarter-circle that decreases orincreases the elevation by a second amount that may be equal to thefirst amount.

In some embodiments, the lid is selectively removable from aninterlocked configuration with the base portion by a user withoutdeforming the lid or base portion. Prior interlocking lids attempt toachieve improved thermal properties by increasing the contact areabetween the base portion and lid, but this is normally at the cost of aneasily removable lid. It has been unexpectedly discovered that whenforming the interfaces as described herein, deliberate application offorce to remove the lid easily removes the lid without breakage byproviding an airflow path into and out of the insulating structure asthe lid is being removed. However, such ease of removal does not come atthe cost of resistance to lid removal by the contents.

In some embodiments, the assembly includes an extension ring configuredto increase the volume of the closed insulated container. The extensionring may have a first extension interface extending along a lower rimthereof, and a second extension interface extending along an upper rimthereof. The first extension interface may be configured to contact andinterlock with the first interface of the base portion by mating atleast one elevation change on the first extension interface with thecorresponding elevation change of the first interface. The secondextension interface may be configured to contact and interlock with thesecond interface of the lid by mating at least one elevation change onthe second extension interface with the corresponding elevation changeof the second interface. The extension ring may therefore be used toincrease the interior volume of the closed insulated container by firstbeing affixed to the base portion prior to affixing the lid. Anextension ring may be desirable when the contents of the closedinsulated container require maintaining a lower temperature for a longerperiod of time, which is typically achieved by the incorporation of morethermal sinks, such as ice packs. Increasing the volume of the closedinsulated container through the addition of an extension ring thereforepermits the inclusion of more ice packs without reducing the quantity ofgoods. Furthermore, the ability to modularly change the internal volumeof the assemblies reduces manufacturing and storage costs by requiringonly the production of a single base portion with a modular volume,instead of configurations of base portions. Further still, manufacturerscan utilize weather forecasts for a particular shipment's destinationand/or itinerary, with or without the aid of automated software, toevaluate the degree of cooling necessary for a particular shipment anddynamically determine whether an extension ring should be included toaccommodate the necessary cooling packs.

In some embodiments, the assembly may be used as a shipper without theaddition of any other structural component. In other embodiments, theinsulating structure may be inserted into and supported by a layer ofcorrugation, such as corrugated cardboard. In some embodiments, theinsulating structure may be surrounded and supported by a layer ofshrink wrap. In some embodiments, the insulating structure may besurrounded and supported by a layer of craft paper.

In another aspect, an insulating assembly may include a base portionhaving a first interface extending along a rim thereof and a lid havinga second interface extending along a rim thereof. The first interfacemay be configured to interlock with the second interface to form aclosed insulated container, and each of the first and second interfacescomprise a single elevation change such that the interlock is formed bymating corresponding elevation changes of the first and secondinterfaces. Each elevation change may comprise a sloped transitionalsection relative to the vertical.

In some embodiments, when the lid is interlocked with the base portion,an upward-facing surface of the lid and an upward-facing surface of thebase portion align with one another to form an upward-facing surface ofthe closed insulated container. As used herein, surfaces “align” when,when the surfaces are positioned proximal to each other, they form anew, flat surface. In this way, the lid may form a “plug-style” lid.

In some embodiments, the corresponding elevation changes of the baseportion and the lid form a half-trapezoid. Thus, at least a portion ofthe lid may be configured to be disposed within the base portion. Insome embodiments, the rim of the lid has a width greater than the rim ofthe base portion so that the lid is a “cap-style” lid.

FIG. 1 is an example of an existing lid-base interface known in the art,commonly referred to as a “zero-clearance” interface 100. When lid 102is removed from base 104 by a user, the 90° angles that form thetransition angles between the flat portions 106, 108 to transitionalsection 110 prevent ingress or egress of air, thereby creating a suctionforce. A heightened degree of force is required by a user, which oftenresults in lid failure.

FIG. 2 is an example of an existing lid-base interface known in the art,commonly referred to as a double-groove interface 200. FIG. 3A is anexample of an existing lid-base interface known in the art, commonlyreferred to as a dovetail interface 300. Interfaces 200 and 300 sufferfrom the same deficiencies as the one depicted in FIG. 1 , namely, thecreation of a suction force as the lid is removed by a user, oftenresulting in breakage as depicted in FIG. 3B.

FIG. 4 is a cross-sectional view of an exemplary lid base interface 400in accordance with the foregoing disclosure. Lid 402 includes non-righttrapezoidal channel 404, and base 406 includes a corresponding non-righttrapezoidal protrusion 408. Trapezoidal channel 404 and trapezoidalprotrusion 406 are formed by a first flat portion 410, firsttransitional section 412, second flat portion 414, second transitionalsection 416, and third flat portion 418. Second flat portion 414 is at adifferent elevation than first flat portion 410 and third flat portion418, such that the channel 404 and protrusion 406 each have twoelevation changes.

First transitional section 412 and second transitional section 416 aresloped and have an angle between about 2° to about 43° relative to thevertical, such as between about 5° to about 20° relative to thevertical. The angle may be 5° relative to the vertical. The slope of thetransition from the first flat portion 410 to the first transitionalsection 412 is 20/1 foam beads or less, as discussed with respect toFIG. 11 . The third flat portion may be level with the first flatportion, or the third flat portion may be higher or lower than the firstflat portion depending on the desired geometry of the lid-baseinterface. The protrusion and channel may be non-right trapezoidal, orthey may have another shape, such as a semi-circle, semi-oval, triangle,or another suitable shape, provided the transitional section has anangle, such as between about 2° to about 43° relative to the vertical.The depiction of the protrusion and channel as having a non-righttrapezoidal shape, to the exclusion of other suitable shapes, is only inthe interest of brevity and is not intended to limit the scope of thedisclosure.

FIG. 5 is a cross-sectional view of an exemplary lid-base interface 500.Lid 502 includes non-right trapezoidal protrusion 504, and base 506includes non-right trapezoidal channel 508. Trapezoidal protrusion 504and trapezoidal channel 506 are formed by a first flat portion 510,first transitional section 512, second flat portion 514, secondtransitional section 516, and third flat portion 518. Second flatportion 514 is at a different elevation than first flat portion 510 andthird flat portion 518, such that the channel 504 and protrusion 506each have two elevation changes. First transitional section 512 andsecond transitional section 516 are sloped and have an angle betweenabout 2° to about 43° relative to the vertical. The slope of thetransition from the first flat portion 510 to the first transitionalsection 512 is 20/1 foam beads or less, as discussed with respect toFIG. 11 .

Insulating assemblies may have a single lid-base interface geometryacross the entire lid-base interface in a particular assembly, i.e., asingle interface geometry extending around the entire rim of the lid andcorresponding base, such that the cross-section of the interface issimilar at any point around the rim of the assembly. Alternatively,assemblies may have a certain lid-base interface geometry along one wallof the assembly, such as the geometry depicted in FIG. 4 , and adifferent lid-base interface geometry along another wall of theassembly, such as the geometry depicted in FIG. 5 . In this way, the lidof a particular insulating assembly may have only limited viableorientations when interlocking with the corresponding base portion.

FIG. 6 is a perspective view in cross-section of an interlockedinsulating assembly 600, comprising closed insulated container 602having a lid 604 and a base 606, enclosing internal volume 608. Theinterface 610 between the lid 602 and base 604 is depicted as resemblingthat depicted in FIG. 4 , but with rounded corners. As describedpreviously, the interface between the lid and base could have aprotrusion on the base, or a protrusion on the lid. The lid-baseinterface geometry may be consistent around the entire perimeter of theinsulating assembly, or it may vary.

FIGS. 7A and 7B depict a lid-base interface 700 before and duringremoval of the lid 702 from the base 706. In FIGS. 7A and 7B, the lid702 is depicted as having a non-right trapezoidal channel 704, and thebase is depicted as having a non-right trapezoidal protrusion 708. Theinterface between lid 702 and base 706 is depicted as a non-righttrapezoid with rounded corners rather than sharp corners, as describedwith reference to FIG. 11 . As the lid 702 is lifted by a user, air ispermitted to enter and/or exit, as shown by the arrows in FIG. 7B. Thisair ingress and egress is immediately possible upon loosening of the liddue to the shape of the protrusion, namely, the angle of thetransitional section being between about 2° to 43° relative to thevertical. As a result, the lid is easily removable without breakage whendeliberate force is applied, but a full, robust thermal seal ismaintained until deliberate force is applied.

FIGS. 8-10 depict exemplary lid-base interfaces that may be used insteadof the trapezoidal interface described previously. In FIGS. 8-10 , a“half-trapezoid” shape is utilized so that the protrusion constitutes asingle elevation change and one or two adjacent flat surfaces. FIG. 8depicts a lid 802 in which at least a portion 804 of the lid 802 isdisposed within the base portion 806. FIG. 9 depicts a “cap-style” lid902 in which the sloped transitional section 904 of lid 902 isconfigured to surround the sloped transitional section 906 of the firstinterface of the base portion 908. FIG. 10 depicts a “plug-style” lid1002, where an upper surface 1006 of the lid 1002 is aligned with anupper surface 1008 of the base portion 1004. In each of FIG. 8-10 , thetransitional section is sloped and has an angle between about 2° to 43°relative to the vertical and the resulting insulating structure realizesthe benefits described herein.

FIG. 11 is a graph showing exemplary lid-base interface slopes that havebeen found to achieve the improved thermal sealing at the lid-baseinterface discussed herein. It has been unexpectedly discovered thatshaping the slope of the lid-base interface to 20 foam beads or less(i.e. an elevation change of 20 beads or less over a horizontal changeof 1 bead or more), the benefits described herein may be realized. FIG.11 depicts a number of exemplary slopes that are 20 foam beads or less,demonstrating the wide variation in shapes that may be utilized in theinsulating structures described herein. In some embodiments, thelid-base interface may have a sharp corner. In other embodiments, thelid-base interface may have a curved or rounded corner. In otherembodiments,

FIG. 12 depicts an exemplary lid-base interface, illustrating thetransitional angles α and β. α and β are each between about 2° and 43°.As described previously, α and β are described as positive angles,regardless of whether the angles are measured clockwise orcounter-clockwise. α and β are depicted in FIG. 12 as being equal to oneanother, but α and β may differ. For example, α may be 4° and β may be20°.

FIG. 13 is a cross-sectional view of an extension ring 1302 insertedbetween a lid 1304 and a base 1306 of an insulating assembly. Extensionring 1302 is configured to increase the volume of a closed insulatedcontainer. Extension ring 1302 and lid 1304 forms a first interface1308, and extension ring 1302 and base 1306 forms a second interface1310. Each of the first interface 1308 and second interface 1310 mayhave a lid-base interface geometry as described herein. The firstinterface and second interface may have identical geometry, as depictedin FIG. 13 , which may increase the modularity of the extension ring andaccompanying lid and base. In other words, the lid 1304 may be placeddirectly on base 1306 because the interface geometries are identical.The first interface and second interface may have different geometrydepending on the intended use of the insulating structure.

FIG. 14 is a perspective view in cross section of an insulating assembly1400 having an extension ring 1402 between a lid 1404 and base 1406.

EXAMPLES

The disclosure may be further understood with reference to the followingnon-limiting examples.

Example 1: ISTA Study to Evaluate Thermal Performance

Three sample insulating assemblies were tested to determine the effectof lid-base interface geometry on the thermal performance of theinsulating structure. The first sample was an EPS box having a densityof 2.0 pcf and a double-groove interface. The second sample was an EPSbox having a density of 1.2 pcf and the non-right trapezoidal interfaceof the present disclosure. The third sample was a PLA box having adensity of 1.2 pcf and the non-right trapezoidal interface of thepresent disclosure. An International Safe Transit Association (ISTA)study was completed on these structures. All dimensions for theinsulating structures were identical besides the density and interfacegeometry. Each insulating structure was filled with the samerefrigerants and a 100 mL water-filled bottle to simulate thetemperature-sensitive payload. Testing was conducted on two structuresof each type following the ISTA 7D 48-hour summer profile and the ISTA7D 48-hour winter profile. The results of the test are presented in FIG.15 .

As shown in FIG. 15 , all insulating structures passed the study.Furthermore, as demonstrated in Table A, the R-values were similardespite a weight reduction of 40%. The R-value of the insulatingstructure may be measured by a specific tool, such as a Fox Heat FlowMeter, available commercially from TA Instruments, New Castle, Del.,USA.

TABLE A Thermal Performance vs. Interface Geometry R-Value (° F. ·ft²/BTU · in) 50° C. 23° C. −10° C. EPS, 2.0 pcf, double-grooveinterface 3.917 4.24 4.50 EPS, 1.2 pcf, interface interface 3.538 3.874.29 PLA, 1.2 pcf, inventive interface 3.529 3.88 4.32

Example 2: Inverted Force Test to Evaluate Interface Strength

As described above, molded foam insulating structures experience“compression creep” over repeated lid removal and replacements,resulting in poor thermal sealing and poor reusability over time. Evenwithout repeated lid removal cycles, these insulating structures mayexperience compression creep over time while the lid is installed sothat a gap forms between the lid and base.

An experiment was performed between two samples. One sample was an EPSbox having the non-right trapezoidal interface described throughout thisdisclosure. One sample was a PLA box having the non-right trapezoidalinterface described throughout this disclosure. Each box was filled with8 pounds of gel packs and inverted for 10 seconds. If the lid failed,the one pound of contents would be removed and the test performed again.If the lid withstood the force of the contents, the box would berestored upright, the lid removed and replaced, and the test repeated.The results of the test are presented below in Table B.

TABLE B Results of Inverted Force Test Test Weight (lbs) Cycle Sample 12 3 4 5 6 7 8 9 10 EPS Box 1 8 2 2 1 1 1 0 0 0 0 EPS Box 2 8 2 1 1 1 1 00 0 0 PLA Box 1 8 8 8 8 8 8 8 8 8 8 PLA Box 2 8 8 8 8 8 8 8 8 8 8

As shown in Table B, the PLA box with the non-right trapezoidalinterface between the base and lid withstood at least 10 cycles ofinversion and lid removal without failing. The EPS box failed on thefirst cycle, and the lid would not remain sealed until only 2 pounds ofcontents remained. No EPS box had a suitable seal after 6 cycles,demonstrating the importance of utilizing high-resiliency materials. Theinability for EPS based containers to withstand inadvertent removalforces has motivated the adoption of the double-groove or “L” shapedinterfaces. These interfaces deliberately increase the force necessaryto remove the lid from an EPS container.

Example 3: Comparison of Inventive Interface with Double-Groove

Two insulated assemblies were constructed out of PLA bead foam, eachwith a density of 1.2 pcf. One sample had a trapezoidal interface asdescribed herein. The other sample had a double-groove interface commonin the industry. Each assembly was filled with identical contents andsubjected to the ISTA 7D summer profile. The results of the test arepresented in FIG. 16 .

The insulated assembly with the inventive trapezoidal interfacemaintained a temperature below 19.5° C. (the critical temperature in theISTA 7D summer profile) for 53.6 hours. In contrast, the insulatedassembly with the double-groove interface maintained a temperature below19.5° C. for only 47 hours. Indeed, as shown in FIG. 16 , the insulatedassembly with the inventive trapezoidal interface maintained a lowertemperature than the assembly with the double-groove interface at everypoint throughout the test, keeping contents up to 6° C. cooler evenafter around 30 hours. Thus, by changing only the interface of theinsulated assembly to the inventive trapezoidal interface, thetemperature of the contents of the insulated assembly can be maintainedbelow 19.5° C. for 14% longer than the double-groove interface.

While the disclosure has been described with reference to a number ofembodiments, it will be understood by those skilled in the art that thedisclosure is not limited to such embodiments. Rather, the disclosurecan be modified to incorporate any number of variations, alterations,substitutions, or equivalent arrangements not described herein, butwhich are commensurate with the spirt and scope of the disclosure.Conditional language used herein, such as “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, generally is intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements or functional capabilities. Additionally, whilevarious embodiments of the disclosure have been described, it is to beunderstood that aspects of the disclosure may include only some of thedescribed embodiments. Accordingly, the disclosure it not to be seen aslimited by the foregoing described, but is only limited by the scope ofthe appended claims.

1. An insulating assembly comprising: a base portion having a firstinterface extending along a rim thereof; and a lid having a secondinterface extending along a rim thereof, wherein the first interface isconfigured to interlock with the second interface to form a closedinsulated container, and wherein each of the first and second interfacescomprise at least one elevation change, such that the interlock isformed by mating corresponding elevation changes of the first and secondinterfaces, wherein each of the elevation changes comprises a slopedtransitional section relative to the vertical.
 2. The assembly of claim1, wherein the sloped transitional section of each elevation change hasa slope of between about 2° to about 43°, relative to the vertical. 3.The assembly of claim 1, wherein the sloped transitional section of eachelevation change has a slope of 5°, relative to the vertical.
 4. Theassembly of claim 1, wherein the base portion is in the form of acontainer having an open end for receiving the lid.
 5. The assembly ofclaim 1, wherein: the base portion and lid are formed from fusedexpandable foam beads, and the transitional section comprises atransition slope of less than 20/1 foam beads.
 6. The assembly of claim1, wherein the base portion and the lid are formed from fused expandablefoam beads comprising at least one of polylactic acid (PLA),polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS),polyethylene terephthalate (PET), polybutylene terephthalate (PBT),rubberized EPS, and other modified EPS.
 7. The assembly of claim 1,wherein the base portion and the lid are formed from a material havingan R-value of at least 3.8° F.·ft²/BTU·in at 23° C.
 8. The assembly ofclaim 1, wherein the closed insulated container passes the ISTA 7D48-hour summer profile and ISTA 7D 48-hour winter profile tests at anoverall weight at least 20% lower than a conventional EPS assembly. 9.The assembly of claim 1, wherein the assembly can be reused at leasttwice as many times as a conventional EPS assembly.
 10. The assembly ofclaim 1, wherein when the lid is interlocked with the base portion, aremoval force necessary for removing the lid changes by less than 10%over 24 hours.
 11. The assembly of claim 1, wherein the first interfacecomprises a protrusion having two elevation changes, and wherein thesecond interface comprises a channel having two elevation changes. 12.The assembly of claim 1, wherein the first interface comprises a channelhaving two elevation changes, and wherein the second interface comprisesa protrusion having two elevation changes.
 13. The assembly of claim 1,wherein the lid is selectively removable from an interlock with the baseportion, without deforming the lid or base portion.
 14. The assembly ofclaim 1, further comprising an extension ring configured to increase thevolume of the closed insulated container, the extension ring having afirst extension interface extending along a lower rim thereof and asecond extension interface extending along an upper rim thereof, whereinthe first extension interface is configured to contact and interlockwith the first interface by mating at least one elevation change on thefirst extension interface with the corresponding elevation change of thefirst interface, and wherein the second extension interface isconfigured to contact and interlock with the second interface by matingat least one elevation change on the second extension interface with thecorresponding elevation change of the second interface.
 15. The assemblyof claim 1, further comprising a corrugated cardboard box into which theclosed insulated container is inserted and secured.
 16. The assembly ofclaim 1, further comprising a layer of shrink wrap disposed on an outersurface of the closed insulated container.
 17. The assembly of claim 1,further comprising a layer of craft paper disposed on an outer surfaceof the closed insulated container.
 18. An insulating assemblycomprising: a base portion having a first interface extending along arim thereof; and a lid having a second interface extending along a rimthereof, wherein the first interface is configured to interlock with thesecond interface to form a closed insulated container, and wherein eachof the first and second interfaces comprise a single elevation change,such that the interlock is formed by mating corresponding elevationchanges of the first and second interfaces, wherein each of theelevation changes comprises a sloped transitional section relative tothe vertical.
 19. The assembly of claim 18, wherein when the lid isinterlocked with the base portion, an upper surface of the lid and anupper surface of the base portion align with one another to form anupper surface of the closed insulated container such that the lid is aplug-style lid.
 20. The assembly of claim 18, wherein the slopedtransitional section of the second interface of the lid is configured tosurround the sloped transitional section of the first interface of thebase portion, opposite an interior volume defined by the closedinsulated container, so that the lid is a cap-style lid.